The role of NADPH oxidase, neuronal nitric oxide synthase and poly(ADP ribose) polymerase in oxidative neuronal death induced in cortical cultures by brain‐derived neurotrophic factor and neurotrophin‐4/5

Abstract

Certain neurotrophins promote or induce oxidative neuronal death in cortical cultures. However, the effector mechanisms mediating this phenomenon have not been delineated. In this study, we investigated the possibility that NADPH oxidase and nitric oxide synthase (NOS) function as such effectors. Western blot analysis showed that treatment with brainderived neurotrophic factor (BDNF) and neurotrophin (NT)-4/5 increased the levels of NADPH oxidase subunits. Moreover, neurotrophin treatment resulted in membrane translocation of p67 phox , a characteristic feature of NADPH oxidase activation. Administration of the specific NADPH oxidase inhibitor, 4-(2-aminoethyl)benzenesulfonylfluoride (AEBSF), attenuated increases in oxygen free radicals thereby suggesting that NADPH oxidase contributes to the oxidative stress induced by neurotrophins. Furthermore, neuronal death induced by BDNF or NT-4/5 was significantly attenuated by AEBSF. Treatment with BDNF has previously been shown to induce neuronal NOS (nNOS). Our data indicated that inhibitors of nNOS attenuated neuronal death induced by BDNF or NT-4/5, consistent with an active role of nNOS in the mediation of neurotrophin neurotoxicity. As in other models of oxidative cell death, BDNF-induced neuronal death was accompanied by poly(ADP ribose) polymerase (PARP) activation. AEBSF or N-nitro-L-arginine (NNA) reduced BDNF-mediated PARP activation. PARP and poly(ADP ribose) glycohydrolase (PARG) are actively involved in mediating neurotrophin neurotoxicity since inhibitors of PARP and PARG significantly reduced levels of cell death. These results suggest that NADPH oxidase and nNOS contribute to increased oxidative stress, subsequent activation of PARP/PARG, and neuronal death induced by prolonged neurotrophin exposure.

Reactive oxygen species generation by the ethylene-bis-dithiocarbamate (EBDC) fungicide mancozeb and its contribution to neuronal toxicity in mesencephalic cells

“…Gao et al (2002) reported a decrease in superoxide levels in rotenone-treated neutrophils preloaded with 5 uM DPI or 0.5 mM APO. Similarly, Hwang et al (2002) reported attenuation in brain-derived neurotrophic factor-induced ROS generation in cortical cultures by 50 uM AEBSF. Although NADPH oxidase inhibitors are relatively nonspecific, the use of 3 different inhibitors with differing mechanisms of action and at concentrations consistent with their selective action on NADPH oxidase support a contribution of the extracellular oxidase in MZ-induced ROS generation.…”

A Novel and Potent Poly(ADP-Ribose) Polymerase-1 Inhibitor, FR247304 (5-Chloro-2-[3-(4-phenyl-3,6-dihydro-1(2H)-pyridinyl)propyl]-4(3H)-quinazolinone), Attenuates Neuronal Damage in in Vitro and in Vivo Models of Cerebral Ischemia

“…at 10 min before MCA occlusion and 10 min before reperfusion markedly inhibited the formation of poly-(ADP-ribose) polymer in cerebral cortex 1 h after reperfusion (D). death without direct inhibition of PARP (Hwang et al, 2002). The DNA alkylating agent-induced NAD depletion is the cause of glycolytic failure and cell death after PARP activation, thus, the maintenance of NAD can mitigate cell death (Ying et al, 2003), suggesting that NAD depletion plays an essential role in the PARP-induced cell death pathway.…”

Inhibition of poly(ADP-ribose) polymerase attenuates the severity of acute pancreatitis and associated lung injury

“…5 Rapid DNA single-stranded breaks are induced by ROS, leading to overactivation of PARP and depletion of cellular energy resulting in mitochondrial free radical generation and cell necrosis. 41,42 In our model, PARP inhibition will also block this process and therefore attenuate cell necrosis (Figure 11). In a third step, severe episodes of acute pancreatitis are associated with a systemic inflammatory response.…”